Khai triển các hằng đẳng thức sau: 4x^2 - 49

In factoring by grouping, what would you have for step 3 for the following? step 1: x^3 +5x^2 +4x+20 step 2: x^2 (x+5)+4(x+5) step 3: ?

What number should be added to the expression x^2+3x+ in order to create a perfect square trinomial? 3/2 3 9/4 9

Rob spent 25%, percent more time on his research project than he had planned. he spent an extra h hours on the project. which of the following expressions could represent the number of hours rob actually spent on the project? two answers